Hello,
welcome to 'Ask a Doctor' service. I've gone through your query and I should tell you right from the start that she has to do what her doctor instructed her to do.
I understand your concern but unfortunately you haven't provide much information about her case - at least not enough - to help me answer your question as accurately as I'd like to. For example you haven't specified the time the symptoms started. Did the symptoms start right after she took the first pill of omeprazole? Did she have similar symptoms earlier?
Omeprazole and many other drugs may cause such symptoms and the doctor should always suspect the drugs for any new symptom a patient presents with. Documenting a side effect though requires taking the following steps:
(a) associating the first symptoms with the first use of the drug
(b) no other good explanation for the symptoms (for example no history of migraines or
abdominal pain)
(c) improvement when stopping the drug (if it's safe to stop it)
(d) new symptoms when starting it again
In some cases not all the steps are necessary and sometimes they can be dangerous (for a serious side effect), so you should let your doctor diagnose her and suggest appropriate action. Until then you'd better stick to your doctor's advice. If her symptoms are severe enough then a visit to the ER is recommended.
I hope I've answered your query! Let me know if I can further assist you.
Kind Regards!